Investigating The Long-chain Polyunsaturated Fatty Acid Biosynthesis Of The Brachyura (Scylla Olivacea And Gecarcoidea Lalandii) Using Transcriptomic And Gene Characterization Approach

Mud crabs is rich in eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA). Utilization of fish oil or trash fish in aquaculture is deemed unsustainable. Hence, vegetable oils (VO) are explored as an alternative to fish oil. VOs are devoid of LC-PUFA, therefore the ability of the animal to de novo synthesize essential fatty acid (EFA) from C18 precursor is important for sustainable aquaculture. Consequently, formulations of diets are impeded by lack of information on elongase (elovl) and desaturase (fads) gene, accumulation of FA in the tissue is often a reflection of dietary fatty acid profile. Therefore, to illustrate the LC-PUFA biosynthesis mechanism, two different crabs (Scylla olivacea and Gecarcoidea lalandii) from different habitats (marine and terrestrial) and with different dietary preference was studied. Results showed that S. olivacea have four elovl subfamilies (elovl1, elovl4, elovl6, and elovl7), Δ9 fads and Δ6-like fads, while G. lalandii have two elovl (elovl1 and elovl6), Δ9 fads, and Δ6-like fads. In both crabs, elovl6 can efficiently convert C18 PUFA, MUFA, and SFA to their subsequent product, with a high conversion rate from C18 to C20. In comparison, S. olivacea elovl4 can elongate C18-C22 PUFA, whereas, in G. lalandii, this function is taken up by elovl1. Intriguingly, S. olivacea elovl1 does not showed any activity towards the exogenous substrate, in comparison, G. lalandii elovl1 can elongate SFA to 26:0, in addition to their ability to elongate PUFA

Effects Of Galactose And Fructose On The Expression Of Isocitrate Lyase (Icl1) Enzyme In Candida Albicans

Sifat kepatogenan dalam C. albicans bergantung kepada atribut kecergasan dan juga faktor-faktor virulen yang lain. Ini termasuk sifat kental terhadap tindak balas tekanan dan penyesuaian metabolik. C. albicans boleh menduduki kebanyakkan persekitaran dalam ruang badan manusia yang mengandungi kepelbagaian sumber karbon yang berbeza. Asimilasi sumber karbon adalah penting untuk pertumbuhan dan juga untuk meneruskan jangkitan. Tesis ini mengkaji kesan galaktosa atau fruktosa terhadap asimilasi sumber karbon sekunder seperti laktat oleh C. albicans. Gen C. albicans Isositrat liase (CaICL1) ditindas oleh penambahan 2% galaktosa atau fruktosa kepada sel-sel yang sedang membiak pada laktat. Gen CaICL1 yang mengekod kitaran glioksilat enzim Icl1 diperlukan untuk pertumbuhan dalam mengunakan sumber karbon sekunder seperti laktat. Enzim CaIcl1 didapati stabil dalam galaktosa tetapi tidak stabil dalam fruktosa. Sebaliknya, kedua-dua galaktosa dan fruktosa mendegradasikan protein S. cerevisiae Icl1 (ScIcl1). The virulence of C. albicans is dependent upon fitness attributes as well as virulence factors. These attributes include robust stress responses and metabolic flexibility. C. albicans can occupy a variety niches in human, many of which contain a range of different carbon sources. The assimilation of these carbon sources is important for growth and essential for establishment of infections by C. albicans. This thesis examines the impact of galactose or fructose upon the assimilation of secondary carbon sources such as lactate by C. albicans Isocitrate lyase gene (CaICL1) is repressed upon addition of 2% galactose or fructose to lactate- grown cells. The CaICL1 gene, which encode the glyoxylate cycles enzymes isocitrate lyase are required for growth on non- fermentable carbon sources such as lactate. However the enzyme CaIcl1 was not destabilized by galactose, but was degraded in response to fructose. In contrast, S. cerevisiae Icl1 (ScIcl1) was rapidly degraded in response to either galactose or fructose

Effect Of Galactose And Fructose On The Expression Of Isocitrate Lyase (ICL1) Enzyme In Candida Albicans

The virulence of C. albicans is dependent upon fitness attributes as well as virulence factors. These attributes include robust stress responses and metabolic flexibility. C. albicans can occupy a variety niches in human, many of which contain a rannge of different carbon sources. The assimilation of these carbon sources is important for growth and essential for establishment of infections by C. albicans. This thesis examines the impact of galactose or fructose upon the assimilation of secondary carbon sources such as lactate by C. albicans Isocitrate lyase gene (CalCLI) is repressed upon addition of 2% galactose or fructose to lactate-grown cells

Metabolic adaptation via regulated enzyme degradation in the pathogenic yeast Candida albicans

The virulence of Candida albicans is dependent upon fitness attributes as well as virulence factors. These attributes include robust stress responses and metabolic flexibility. The assimilation of carbon sources is important for growth and essential for the establishment of infections by C. albicans. Previous studies showed that the C. albicans ICL1 genes, which encode the glyoxylate cycle enzymes isocitratelyase are required for growth on non-fermentable carbon sources such as lactate and oleic acid and were repressed by 2% glucose. In contrast to S. cerevsiae, the enzyme CaIcl1 was not destabilised by glucose, resulting with its metabolite remaining at high levels. Further glucose addition has caused CaIcl1 to lose its signal and mechanisms that trigger destabilization in response to glucose. Another purpose of this study was to test the stability of the Icl1 enzyme in response to the dietary sugars, fructose, and galactose. In the present study, the ICL1 mRNAs expression was quantified using Quantitative Real Time PCR, whereby the stability of protein was measured and quantified using Western blot and phosphoimager, and the replacing and cloning of ICL1 ORF by gene recombination and ubiquitin binding was conducted via co-immuno-precipitation. Following an analogous experimental approach, the analysis was repeated using S. cerevisiaeas a control. Both galactose and fructose were found to trigger the degradation of the ICL1 transcript in C. albicans. The Icl1 enzyme was stable following galactose addition but was degraded in response to fructose. C. albicans Icl1 (CaIcl1) was also subjected to fructose-accelerated degradation when expressed in S. cerevisiae, indicating that, although it lacks a ubiquitination site, CaIcl1 is sensitive to fructose-accelerated protein degradation. The addition of an ubiquitination site to CaIcl1 resulted in this enzyme becoming sensitive to galactose-accelerated degradation and increases its rate of degradation in the presence of fructose. It can be concluded that ubiquitin-independent pathways of fructose-accelerated enzyme degradation exist in C. albicans

Long-chain polyunsaturated fatty acid biosynthesis in a land-crab with advanced terrestrial adaptations: Molecular cloning and functional characterization of two fatty acyl elongases

Depending on the presence and activities of the front-end fatty acyl desaturases and elongation of very long-chain fatty acid (Elovl) enzymes, animals have different capacities for long-chain (≥C20) polyunsaturated fatty acids (LC-PUFA) biosynthesis. Successful land colonisation in brachyuran crabs requires a shift towards terrestrial food chain with limited LC-PUFA availability. We cloned and functionally characterised two elovl genes from the purple land crab Gecarcoidea lalandii. The two Elovl contained all the necessary motifs of a typical polyunsaturated fatty acids (PUFA) Elovl and phylogenetically clustered in the Elovl1 and Elovl6 clades, respectively. The G. lalandii Elovl1 elongated saturated fatty acids, with low activities towards C20 and C22 PUFA substrates. Moreover, the G. lalandii Elovl6 was particularly active in the elongation of C18 PUFA, although it also recognised monounsaturated fatty acids as substrates for elongation. Collectively, the herein characterised G. lalandii elovl paralogues fulfil all the elongation steps involved in the LC-PUFA biosynthetic pathways. Tissue distribution of the G. lalandii elovl genes, along with the FA composition analyses, suggest the hepatopancreas and gill as key metabolic sites for fatty acid elongation. However, current data suggest that G. lalandii is unable to rely solely on biosynthesis to fulfil LC-PUFA requirements, since front-end desaturase appears to be absent in this species and other decapods.We are grateful to the Ministry of Higher Education Malaysia for Fundamental Research Grant Scheme with Project Code: FRGS/1/2018/STG05/USM/01/4. Moreover, this study was partly funded through the project IMPROMEGA of the Ministry of Science, Innovation and Universities, Spanish Government (RTI2018-095119-B-100, MCIU/AEI/FEDER/UE). We also thank Universiti Sains Malaysia for the appointment of Óscar Monroig as Adjunct Academic Fellow USM. 9/1/v Jld. XIII)

Complete mitogenome of Uca rosea and Uca paradussumieri, and their implications in evolution history of fiddler crab in Ocypodidae

We determined the complete mitogenomes of two fiddler crabs Uca rosea (15,643 bp) and Uca paradussumieri (15,614 bp) of Ocypodidae within Brachyura. Both consist of 37 genes (13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes and one control region). The mitogenomes composition of U. rosea and U. paradussumieri are highly A + T biased, 70.77% and 71.12%, respectively, and showed positive AT (0.03 and 0.02) and negative GC (−0.29 and −0.24) skews. Phylogenetic analysis showing all the fiddler crabs were under monophyletic group relationship and belong to Ocypodidae; U. rosea has a sister group relationship with U. paradussumieri